Remote control system with verification capability

ABSTRACT

A system for operating actuators, such as electrically operable door locks, at one or more remote stations by means of a control unit at a central station. A lock signal of predetermined frequency is generated upon operation of a lock button on the control unit. The lock signal is supplied to the remote station via a main communication channel to deenergize power units on the doors and permit the spring-loaded door locks to lock. An indicator lamp is provided at the central station to verify the proper locking of the doors upon reception of a return signal from the remote station. To open the doors, an unlock signal of another predetermined frequency is supplied to the remote station via the main communication channel line to energize the power units and overcome the spring forces on the locks. The unlock signal is initiated upon operation of an unlock button on the central station control unit or by operation of an unlock button on a second control unit at the remote station. A signal of a third predetermined frequency is supplied upon operation of a night control button on the central station control unit to open a designated door at the remote station used for authorized night entry.

I United States Patent [1113 622 998 [72] Inventors Joe M. Kortman;3,472,965 1 6/1969 Blossom ..L 340/147X Joseph schumn both Vancouverwash Primary ExaminerDonald J. Yusko [21] 154% Attorney-Kolisch &Hartwell [22] Filed Mar. 2, 1970 [45] Patented Nov. 23, 1971 1 AssigneesBum"! y Tm the ABSTRACT: A system for operating actuators, such as elec-Tnms trically operable door locks, at one or more remote stations byTmma; means of a control unit at a central station. A lock signal of 1 9schuldnaMeraam A'schukini predetermined frequency is generated uponoperation of a vamvel" wflsh- P interest mead! lock button on thecontrol unit. The lock signal is supplied to the remote station via amain communication channel to deenergize power units on the doors andpermit the spring- [54] WITH loaded door locks to lock. An indicatorlamp is provided at the central station to verify the proper locking ofthe doors upon 4 Claims 4 Drawing reception of a return signal from theremote station. To open [52] US. Cl 340/1171 R, the doors, an unlocksignal of another predetermined frequen- 343/225 cy is supplied to theremote station via the main communica- [51] lnt.Cl H041 9/00, tionchannel line to energize the power units and overcome G08b 5/00 thespring forces on the locks. The unlock signal is initiated [50] F leldof Search 340/ l 7 1 upon operation of an unlock button on the centralstation con- 147, 408, 226; 343/225, 228 trol unit or by operation of anunlock button on a second control unit at the remote station. A signalof a third predeter- Rdemms Cited mined frequency is supplied uponoperation of a night control UNITED STATES PATENTS button on the centralstation control unit to open a designated 3,371,316 2/1968 Johnson340/171 door at the remote station used for authorized night entry.

MA/A/ Ame aw)?" REMOTE CONTROL SYSTEM WITH VERIFICATION CAPABILITYBACKGROUND OF THE INVENTION The present invention concerns a system foroperating and monitoring the condition of electrically energizabledevices at one or more remote stations from a control unit at a centralstation. A preferred embodiment of the system is described inconjunction with controlling electrically actuatable door locks.

Systems have been proposed in the prior art for automatically operatingdevices at remote stations by means of controls at a central station.Generally, it is desirable that such systems be fail-safe in the sensethat power failure or system failure leaves the controlled elements in apreferred or safe position. Furthermore, it is desirable to provideindicator means in such a system for an operator to verify the correctoperation of the system. Finally, it is desirable to provide means foran operator at a remote station to carry out independently certaincontrol operations without compromising the security afforded by centralstation control.

Generally, the remote-central station control systems known in the priorart have omitted one or more of the above features and have not beencharacterized by good reliability. Furthermore, prior art systems areusually complex and so expensive that the cost of their use in otherthan the most sophisticated applications is prohibitive.

OBJECTS OF THE INVENTION Accordingly, it is an object of the inventionto provide an improved and simplified system for operating electricallyenergizable devices at one or more remote stations by means of a controlunit located at a central station.

It is another object of the invention to provide such a system whichafiords positive verification of the state or condition of a remotelycontrolled device.

It is a further object of the invention to provide a system of the typedescribed wherein verification errors are minimized.

A preferred embodiment, as described herein, is used in conjunction withlocking and unlocking remote door locks which are electricallyactuatable. The locks are of a type which are fail-safe, in the sensethat on the removal of energizing power, the locks automatically lock.Signalers are provided at a central station in the system which transmitsignals for locking and unlocking one or more locks. A signaler at aremote station where controlled locks are located transmits a signal toa receiver at the central station to indicate when the locks are locked.Means are provided at the central station which prevents the occurrenceof a locked-condition indication unless the remote locks have in factlocked.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of theinvention will become apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram of a central control station employing theinvention;

FIG. 2 is a block diagram of a remote station employing the invention;

FIG. 3 is a table showing the instantaneous conditions of variouselements of the remote and central stations during operation of thesystem; and

FIG. 4 is a block diagram of a system which includes two remote stationsdesigned in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, thepreferred embodiment of the invention is used in conjunction with anelectrical locking system which includes a central station as shown inFIG. I and one or more remote stations, each comprising elementsarranged as shown in FIG. 2. For purposes of explanation, the elementsof the central and remote stations are shown in their normallydeenergized conditions.

A main communication channel 10 interconnects the central station andeach of the remote stations of the system. While only a single remotestation is shown in the preferred embodiment, as many additional remotestations as are desired can be added to the system. Generators 12, 14,and 16 of the central station are selectively isolated from the mainline by a relay-controlled switch 18 including an actuating winding 19and a normally open contact 20 in the main line. Control buttons 22, 24and 26 are provided having first terminals connected, respectively, togenerators 12, 14, and 16; and second tenninals connected to a DC powersupply 28. A common power circuit is provided from the control buttonsto switch 18 including lines 30 and diodes 31, 32, and 33 poled topermit current flow as shown. Operation of any of the control buttons22, 24, 26 closes its contacts providing power to the generatorassociated therewith, and simultaneously providing power to winding 19to close contact 20.

All the generators are of conventional design. Generator I2 selectivelyprovides a 730 cycle AC signal; generator 14 selectively provides a 400cycle AC signal; and generator 16 selectively provides a 960 cycle ACsignal. In the embodiment illustrated, a signal from generator 12 isemployed to lock all doors at the remote station; generator 14 to unlockone of these doors for authorized night-entry purposes; and generator 16to unlock all such doors. The manner in which signals from thesegenerators effect operation of the locks at the remote station isexplained hereinafter.

Line 35 connects the main channel 10 to an input of preamplifier 36, andlines 38 connect the output of the preamplifier to input terminals of areceiver 40 and a receiver 42. Receiver 40 is a frequency-selectiveamplifier designed to produce a positive DC output in response toreceiving at its input a 960 cycle AC signal, and to produce a zerooutput in response to all other inputs. Receiver 42 is also afrequency-selective amplifier, designed to produce a positive DC outputin response to a 1300 cycle input signal, and to produce a zero outputin response to all other inputs.

Line 44 connects the output of receiver 40 to the B input terminal of adual input gate 46, and line 48 connects the output of receiver 42 tothe A input terminal of a dual-input gate 50. The A input terminal ofgate 46 is connected to the input side of generator 12 via line 34 anddiode 47, and the output of gate 46 is connected to the B input terminalof gate 50 by line 51. Line 54 connects the output ofgate 50 to oneterminal of an indicator lamp 55, which has another terminal grounded.

Gate 46 is a conventional unit designed to produce a positive level orONE output on closing of the switch actuated by control button 22 and,simultaneously, the absence of a positive DC signal at the B input. Gate46 produces a low level or ZERO output in the absence of a signal at theA input or in response to a positive DC inhibit pulse at the B input.Once the output of gate 46 is set to a ONE level it will remain in thatstate until a ONE or inhibit signal is applied to the B input terminal.

Gate 50 is a conventional-type dual-input gate which functions somewhatdifferently than gate 46. The output of the gate is placed in a ONEstate on ONE state voltages being placed simultaneously on both inputs.The output of the gate remains in a ONE state thereafter so long as aONE state remains on the B input. In the absence of a ONE state on the Binput, the output is in a ZERO state regardless of the condition of theA input.

With the output of gate 50 in a ONE state, lamp 55 is energized.

Referring now to FIG. 2, main channel 10 is shown connected to an inputterminal of an amplifier 60. Lines 61, 62 connect the output ofamplifier 60 to input terminals of receivers 66, 68, and 70. Amplifier60 is a conventional unit and receivers 66, 68, and 70 are conventionalfrequencyselective amplifiers similar in design to receivers 40 and 42.Receiver 66 produces a positive DC output signal in response toreceiving a 960 cycle AC input. Likewise, receiver 68 produces apositive DC output signal in response to receiving a 730 cycle AC input;a receiver 70 produces a positive DC output signal in response toreceiving a 400 cycle AC input. Line 72 connects the output of receiver66 to the A input terminal of a gate 76 which is substantially the sameas gate 46, and line 73 connects the output of receiver 68 to the B orinhibit input terminal of gate 76. Line 73 also connects the output ofreceiver 68 to an input terminal of a conventional timer 77.

Timer 77 is a unit designed to produce a DC output pulse of fixedduration, beginning on removal of a positive DC input signal on line 73from receiver 68. Line 63 connects the output of the timer throughnormally closed contacts 83 to an input terminal of a 1300 cycle ACgenerator 64. Line 65 returns the output of generator 64 tomain channel10.

Line 74 connects the output of gate 76 to an input terminal of relay 80,relay 82, and relay 84. Line 75 connects the output of receiver 70 tothe input terminal of relay 84. A diode 86 is provided in line 74between relays 82 and 84 to block the output of receiver 70 from relays80 and 82.

As shown by the dotted lines, a set of normally open contacts 8l areassociated with relay 80. Normally closed contacts 83 are associatedwith relay 82. And normally open contacts 85 are associated with relay84. When relay 80 is energized contacts 81 close and voltage is suppliedfrom a source, not shown, via line 87 to a plurality of power units 88,each associated with a main door look at the remote station. Whenenergized, the power units have sufficient force to overcome the forceof spring members on the door locks and unlock the doors. However, whenthe power units are deenergized with the doors in a closed position, thespring-loaded locks move into their locked positions.

In similar fashion, the energization of relay 84 closes contacts 85whereby voltage is supplied from a source, not shown, via line 89 to apower unit 90 associated with a door designated for night use at theremote station. Energization of relay 82 opens contacts 83 andinterrupts the circuit between timer 77 and generator 64.

Controlswitch 91 is part of an outside control unit hidden near theremote station. One contact of switch 91 is connected to a DC source notshown, and line 92 connects the other contact of the switch to the inputterminal of a generator 94. Generator 94, when energized, provides a 960cycle AC output signal. The output of the generator is returned to mainchannel 10 via line 96, for a purpose to be explained.

Various operations of the system will now be explained in conjunctionwith the table shown in FIG. 3. The table shows the instantaneous stateof various elements of the system during the various cycles of operationof the system. To lock the main doors, button 22 at the central stationis depressed, whereby generator 12 is energized and provides a 730 cycleAC lock signal. Winding I9 is energized by actuation of button 22, andcontact 20 of switch 18 closes to supply the lock signal to the remotestation via main channel 10.

Closing of the switch associated with button 22 also supplies a ONEinput to the A terminal of gate 46. Since there is then a ZERO on the Binput of gate 46, the output of the gate has a ONE on it. The output ofgate 50 is in a ZERO state since its A input is in a ZERO state.Therefore, lamp 55 is not energized.

The 730 cycle lock signal on the main channel is detected at the remotestation by receiver 68 which provides a ONE input to the B inputterminal of gate 76. Accordingly, the output of gate 76 is at a ZEROlevel and relays 80 and 82 are deenergized. With relay 80 in adeenergized condition, contacts 81 assume their normally open states andthe power units for the main door locks are deenergized. Consequently,the springloaded locks move to their locked position.

At the same time, the ONE output of receiver 68 is supplied to timer 77,setting the latter. On removal of this ONE output from the inputterminal of the timer the timer 77 produces a DC output pulse of fixedduration. Since relay 82 is deenergized, contacts 83 reside in anormally closed position and the output of timer 77 is supplied togenerator 64. Generator 64 is actuated by the timer pulse and produces a1300 cycle AC verification signal during the l-to'2-second duration ofthe timer pulse. The output of generator 64 is returned to the mainchannel and the central station where it is detected by receiver 42. Thetime interval afforded by timer 77 ensures proper and complete receptionof a lock signal, and operation of the door locks, before alock-verification signal can be returned to the central station. This isimportant in minimizing the chances for an error in the operation of thesystem.

In particular. the time interval mentioned assures that alock-verification signal is not transmitted to line, or main channel, 10while a lock signal is still on the line. It thus positively preventsthese two types of signals from overlapping in time, and frominterfering with one another. As an important consequence, a single line10) only is required to handle both signals, and this greatly simplifiesand reduces the cost of an installation employing the invention. Theduration of an output signal of the timer is selected to ensure properreception of a verification signal at the central station.

In response to the 1300 cycle verification signal, receiver 42 producesa ONE output which is supplied to the A input terminal of gate 50. Sincethe B input terminal of gate 50 is also at a ONE level, gate 50 producesa positive DC or ONE output which lights lamp 55 as an indication thatthe doors have properly locked. So long as the relays controlling thedoor locks are deenergized, the lamp remains lit.

To unlock the doors, button 26 at the central station is depressed bythe operator to actuate generator 16 and provide a 960 cycle ACunlocking signal to the main channel. The unlocking signal is detectedat the remote station by receiver 66 which produces a positive DC or ONEoutput in response thereto. The ONE output of receiver 66 is supplied tothe A input terminal of gate 76. In the absence of a 730 cycle signal,the B input of gate 76 is at a ZERO level. Consequently, a ONE output isproduced by gate 76 at its output, and supplied via line 74 to energizerelays 80, 82, and 84. Energization of relay 80 closes contacts 81 andprovides voltage to power units 88 which unlocks the main doors.Energization of relay 84 closes contacts and supplies voltage to unlockthe night door. Energization of relay 82 opens contacts 83.

The 960 cycle unlock signal is also detected by receiver 40 at thecentral station which provides a ONE input to the B terminal of gate 46.As a consequence, the outputs of gates 46, 50 are placed at a ZEROlevel, and lamp 55 is deenergized to indicate that the doors areunlocked.

Operation of switch 91 at the remote station also provides a 960 cycleAC unlocking signal to the main channel which serves to unlock the maindoors and night door in the manner just explained.

Control switch 91 is preferably hidden outside the remote station in alocation known only to authorized persons. Accordingly, the switch canbe utilized to provide an unlock signal for all the doors at the remotestation without compromising the security of the system.

It will be noted that if, subsequent to transmission of a lock signalfrom generator 12, and prior to reception by receiver 42 of averification signal, an unlock signal is transmitted by either ofgenerators 16 or 94, lamp 55 will not light up. This is because receiver40 will place an inhibit signal on the B input of gate 46, resulting inthe application of a ZERO state voltage to the B input of gate 50. Inorder for the lamp to light, a proper verification signal must bereceived in receiver 42 subsequent to transmission of a lock signal bygenerator 12, without an intervening unlock signal. Because of this typeaction, good reliability is assured.

Should it be desired to admit a watchman through the night door during atime when all the doors are locked, this may be accomplished bydepression of button 24 at the central station, in response to a phonecall or some other suitable authorization signal. When button 24 isoperated generator 14 is energized to provide a 400 cycle AC nightunlock signal to the main channel which is detected by receiver 70. Aslong as button 24 is depressed, the output of receiver 70 is at apositive DC level. The positive DC signal from receiver 70 energizesrelay 84 whereby contacts 85 are closed and the night door is unlocked.Upon release of button 24 the night door is relocked.

Alternatively, means may be provided to automatically operate button 24for a predetermined entry period in response to a coded authorizationsignal sent by the watchman, to the central station via a conventionaltelephone circuit or by a separate communications circuit.

If desired, the central station of the invention can be used to controlmore than one remote stations. Such an arrangement is shownschematically in FIG. 4. In the embodiment shown, each remote station(which is substantially the same in construction as the remote stationshown in FIG. 2) is connected to the central station (which issubstantially the same in construction as the central station shown inFIG. 1) by a separate communication channel l0, A switch is provided atthe central station for selection, by the operator, of the remotestation or stations to be controlled upon a given control cycle. It isalso within the scope of the invention to provide plural remotestations, each of which is responsive to a different set of controlfrequencies from the central station.

The system described is fail-safe in the sense that failure of the powersupply for the main door power units or failure of the control circuitrywill result in the opening of contacts 81 and 85 whereby the doors arelocked. Furthermore, the system is secure in that a night door may beindependently unlocked at each remote station to permit entry of anauthorized person, in response to a proper signal received at thecentral station from the remote station. Finally, a separate, hiddencontrol switch is provided at the remote station which may be used byauthorized persons to unlock the doors, without compromising thesecurity of the system.

While a preferred embodiment has been described in conjunction with alocking system, the control system of the invention may be used toactuate a variety of other devices at one or more remote stations.Likewise the use of AC generators or predetermined output frequency isnot mandatory. Pulse coded lock and unlock signals generated by suitablemeans could be used as well.

lt is claimed and desired to secure by Letters Patent:

1. A system for controlling and monitoring from one location the stateof an electrically energizable device at a remote location comprising apair of signalers with one at said one location and the other at saidremote location, said other signaler being operatively connected to saiddevice and switching automatically to a signal-producing state followingplacement of said device in one state, and returning automatically to anonsignal producing state with placement of said device in anotherstate,

a pair of receivers, each for receiving a signal from a differentsignaler, with one receiver at said other location for receiving asignal from said one signaler, and the other receiver at said onelocation for receiving a signal from said other signaler, said onereceiver being operatively connected to said device for effectingplacement thereof in its said one state on the receiver receiving asignal from said one signaler,

an indicator at said one location having indicating and nonindicatingstates, and

interconnecting means at said one location operatively interconnectingsaid one signaler, said other receiver and said indicator effective toplace the latter in its said indicating state on reception by said otherreceiver of a signal from said other signaler following transmission tosaid one receiver of a signal from said one signaler.

2. The system of claim 1 which further comprises a third signaler atsaid one location, and a third receiver at said remote location forreceiving a signal from said third signaler and operatively connected tosaid device, said third receiver on receiving a signal from said thirdsignaler effecting placement of said device in its said other state.

3. The system of claim 2, wherein said interconnecting means isoperatively connected to said third signaler and is effectlve to inhibitplacement of said indicator in its said indicating state in a case wheretransmission of a signal from said third signaler occurs subsequent totransmission of a signal from said one signaler and prior to receptionof a signal by said other receiver.

4; The system of claim 3, wherein said device comprises part of a doorlock mechanism which further includes a lock having locked and unlockedstates, and said device when in its said one state places said lock inits said locked state.

1. A system for controlling and monitoring from one location the stateof an electrically energizable device at a remote location comprising apair of signalers with one at said one location and the other at saidremote location, said other signaler being operatively connected to saiddevice and switching automatically to a signal-producing state followingplacement of said device in one state, and returning automatically to anonsignal producing state with placement of said device in anotherstate, a pair of receivers, each for receiving a signal from a differentsignaler, with one receiver at said other location for receiving asignal from said one signaler, and the other receiver at said onelocation for receiving a signal from said other signaler, said onereceiver being operatively connected to said device for effectingplacement thereof in its said one state on the receiver receiving asignal from said one signaler, an indicator at said one location havingindicating and nonindicating states, and interconnecting means at saidone location operatively interconnecting said one signaler, said otherreceiver and said indicator effective to place the latter in its saidindicating state on reception by said other receiver of a signal fromsaid other signaler following transmission to said one receiver of asignal from said one signaler.
 2. The system of claim 1 which furthercomprises a third signaler at said one location, and a third receiver atsaid remote location for receiving a signal from said third signaler andoperatively connected to said device, said third receiver on receiving asignal from said third signaler effecting placement of said device inits said other state.
 3. The system of claim 2, wherein saidinterconnecting means is operatively connected to said third signalerand is effective to inhibit placement of said indicator in its saidindicating state in a case where transmission of a signal from saidthird signaler occurs subsequent to transmission of a signal from saidone signaler and prior to reception of a signal by said other receiver.4. The system of claim 3, wherein said device comprises part of a doorlock mechanism which further includes a lock having locked and unlockedstates, and said device when in its said one state places said lock inits said locked state.